Construction Knowledge Series: What is "Grout"?

If you think can clearly define the term grout, you are going to be wrong most of the time.

Grout is a generic term used on a construction site that typically describes a cementitious sand mixture without coarse aggregates.  However, different trades call different materials grout. 

-  To a tile setter, grout is the cementitious sand mixture holding the tiles in place and filling the gaps between the tile.

-  To a mason, the cementitious sand mixture between block and brick is called mortar.  A mason would say that grout is the high slump concrete used to fill CMU (Concrete Masonry Units) walls.  Unlike most other types of grout, CMU infill grout often has coarse aggregate such as pea gravel included in the mix.

-  To an underground pipe layer, grout is the cementitious sand mixture used in a manhole to create a watertight seal at seams and where pipes come into the structure.

-  To someone installing concrete, grout is often used as concrete infill added after an initial concrete pour.  You will hear of tradespeople “grouting” in an embed.

I’m confident there are numerous other definitions of grout, but you get the picture. To define grout clearly and accurately, you must have the context of which trade is using the term grout.